//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___RANDOM_GEOMETRIC_DISTRIBUTION_H
#define _LIBCPP___RANDOM_GEOMETRIC_DISTRIBUTION_H

#include <__config>
#include <__random/is_valid.h>
#include <__random/negative_binomial_distribution.h>
#include <iosfwd>
#include <limits>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

template<class _IntType = int>
class _LIBCPP_TEMPLATE_VIS geometric_distribution
{
    static_assert(__libcpp_random_is_valid_inttype<_IntType>::value, "IntType must be a supported integer type");
public:
    // types
    typedef _IntType result_type;

    class _LIBCPP_TEMPLATE_VIS param_type
    {
        double __p_;
    public:
        typedef geometric_distribution distribution_type;

        _LIBCPP_INLINE_VISIBILITY
        explicit param_type(double __p = 0.5) : __p_(__p) {}

        _LIBCPP_INLINE_VISIBILITY
        double p() const {return __p_;}

        friend _LIBCPP_INLINE_VISIBILITY
            bool operator==(const param_type& __x, const param_type& __y)
            {return __x.__p_ == __y.__p_;}
        friend _LIBCPP_INLINE_VISIBILITY
            bool operator!=(const param_type& __x, const param_type& __y)
            {return !(__x == __y);}
    };

private:
    param_type __p_;

public:
    // constructors and reset functions
#ifndef _LIBCPP_CXX03_LANG
    _LIBCPP_INLINE_VISIBILITY
    geometric_distribution() : geometric_distribution(0.5) {}
    _LIBCPP_INLINE_VISIBILITY
    explicit geometric_distribution(double __p)
        : __p_(__p) {}
#else
    _LIBCPP_INLINE_VISIBILITY
    explicit geometric_distribution(double __p = 0.5)
        : __p_(__p) {}
#endif
    _LIBCPP_INLINE_VISIBILITY
    explicit geometric_distribution(const param_type& __p) : __p_(__p) {}
    _LIBCPP_INLINE_VISIBILITY
    void reset() {}

    // generating functions
    template<class _URNG>
        _LIBCPP_INLINE_VISIBILITY
        result_type operator()(_URNG& __g)
        {return (*this)(__g, __p_);}
    template<class _URNG>
        _LIBCPP_INLINE_VISIBILITY
        result_type operator()(_URNG& __g, const param_type& __p)
        {return negative_binomial_distribution<result_type>(1, __p.p())(__g);}

    // property functions
    _LIBCPP_INLINE_VISIBILITY
    double p() const {return __p_.p();}

    _LIBCPP_INLINE_VISIBILITY
    param_type param() const {return __p_;}
    _LIBCPP_INLINE_VISIBILITY
    void param(const param_type& __p) {__p_ = __p;}

    _LIBCPP_INLINE_VISIBILITY
    result_type min() const {return 0;}
    _LIBCPP_INLINE_VISIBILITY
    result_type max() const {return numeric_limits<result_type>::max();}

    friend _LIBCPP_INLINE_VISIBILITY
        bool operator==(const geometric_distribution& __x,
                        const geometric_distribution& __y)
        {return __x.__p_ == __y.__p_;}
    friend _LIBCPP_INLINE_VISIBILITY
        bool operator!=(const geometric_distribution& __x,
                        const geometric_distribution& __y)
        {return !(__x == __y);}
};

template <class _CharT, class _Traits, class _IntType>
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os,
           const geometric_distribution<_IntType>& __x)
{
    __save_flags<_CharT, _Traits> __lx(__os);
    typedef basic_ostream<_CharT, _Traits> _OStream;
    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
               _OStream::scientific);
    return __os << __x.p();
}

template <class _CharT, class _Traits, class _IntType>
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is,
           geometric_distribution<_IntType>& __x)
{
    typedef geometric_distribution<_IntType> _Eng;
    typedef typename _Eng::param_type param_type;
    __save_flags<_CharT, _Traits> __lx(__is);
    typedef basic_istream<_CharT, _Traits> _Istream;
    __is.flags(_Istream::dec | _Istream::skipws);
    double __p;
    __is >> __p;
    if (!__is.fail())
        __x.param(param_type(__p));
    return __is;
}

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP___RANDOM_GEOMETRIC_DISTRIBUTION_H
